/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  X.509 common functions for parsing and verification
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 *  The ITU-T X.509 standard defines a certificate format for PKI.
 *
 *  http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
 *  http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
 *  http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
 *
 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
 */

#include "tls/config.h"

#if defined(MBEDTLS_X509_USE_C)

#include "tls/x509.h"
#include "tls/asn1.h"
#include "tls/oid.h"

#include <stdio.h>
#include <string.h>

#if defined(MBEDTLS_PEM_PARSE_C)
#include "tls/pem.h"
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "tls/platform.h"
#else
#include <stdio.h>
#include <stdlib.h>
#define mbedtls_free      free
#define mbedtls_calloc    calloc
#define mbedtls_printf    printf
#define mbedtls_snprintf  snprintf
#endif

#if defined(MBEDTLS_HAVE_TIME)
#include "tls/platform_time.h"
#endif

#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
#include <windows.h>
#else
#include <time.h>
#endif

#if defined(MBEDTLS_FS_IO)
#include <stdio.h>
#if !defined(_WIN32)
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#endif
#endif

#define CHECK(code) if ((ret = code) != 0) {return(ret); }
#define CHECK_RANGE(min, max, val) if (val < min || val > max) {return(ret); }

/*
 *  CertificateSerialNumber  ::=  INTEGER
 */
int mbedtls_x509_get_serial(unsigned char **p, const unsigned char *end, mbedtls_x509_buf *serial)
{
	int ret;

	if ((end - *p) < 1) {
		return (MBEDTLS_ERR_X509_INVALID_SERIAL + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	if (**p != (MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_PRIMITIVE | 2) && **p != MBEDTLS_ASN1_INTEGER) {
		return (MBEDTLS_ERR_X509_INVALID_SERIAL + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
	}

	serial->tag = *(*p)++;

	if ((ret = mbedtls_asn1_get_len(p, end, &serial->len)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_SERIAL + ret);
	}

	serial->p = *p;
	*p += serial->len;

	return (0);
}

/* Get an algorithm identifier without parameters (eg for signatures)
 *
 *  AlgorithmIdentifier  ::=  SEQUENCE  {
 *       algorithm               OBJECT IDENTIFIER,
 *       parameters              ANY DEFINED BY algorithm OPTIONAL  }
 */
int mbedtls_x509_get_alg_null(unsigned char **p, const unsigned char *end, mbedtls_x509_buf *alg)
{
	int ret;

	if ((ret = mbedtls_asn1_get_alg_null(p, end, alg)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	return (0);
}

/*
 * Parse an algorithm identifier with (optional) paramaters
 */
int mbedtls_x509_get_alg(unsigned char **p, const unsigned char *end, mbedtls_x509_buf *alg, mbedtls_x509_buf *params)
{
	int ret;

	if ((ret = mbedtls_asn1_get_alg(p, end, alg, params)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	return (0);
}

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
/*
 * HashAlgorithm ::= AlgorithmIdentifier
 *
 * AlgorithmIdentifier  ::=  SEQUENCE  {
 *      algorithm               OBJECT IDENTIFIER,
 *      parameters              ANY DEFINED BY algorithm OPTIONAL  }
 *
 * For HashAlgorithm, parameters MUST be NULL or absent.
 */
static int x509_get_hash_alg(const mbedtls_x509_buf *alg, mbedtls_md_type_t *md_alg)
{
	int ret;
	unsigned char *p;
	const unsigned char *end;
	mbedtls_x509_buf md_oid;
	size_t len;

	/* Make sure we got a SEQUENCE and setup bounds */
	if (alg->tag != (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
	}

	p = (unsigned char *)alg->p;
	end = p + alg->len;

	if (p >= end) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	/* Parse md_oid */
	md_oid.tag = *p;

	if ((ret = mbedtls_asn1_get_tag(&p, end, &md_oid.len, MBEDTLS_ASN1_OID)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	md_oid.p = p;
	p += md_oid.len;

	/* Get md_alg from md_oid */
	if ((ret = mbedtls_oid_get_md_alg(&md_oid, md_alg)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	/* Make sure params is absent of NULL */
	if (p == end) {
		return (0);
	}

	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_NULL)) != 0 || len != 0) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	if (p != end) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
	}

	return (0);
}

/*
 *    RSASSA-PSS-params  ::=  SEQUENCE  {
 *       hashAlgorithm     [0] HashAlgorithm DEFAULT sha1Identifier,
 *       maskGenAlgorithm  [1] MaskGenAlgorithm DEFAULT mgf1SHA1Identifier,
 *       saltLength        [2] INTEGER DEFAULT 20,
 *       trailerField      [3] INTEGER DEFAULT 1  }
 *    -- Note that the tags in this Sequence are explicit.
 *
 * RFC 4055 (which defines use of RSASSA-PSS in PKIX) states that the value
 * of trailerField MUST be 1, and PKCS#1 v2.2 doesn't even define any other
 * option. Enfore this at parsing time.
 */
int mbedtls_x509_get_rsassa_pss_params(const mbedtls_x509_buf *params, mbedtls_md_type_t *md_alg, mbedtls_md_type_t *mgf_md, int *salt_len)
{
	int ret;
	unsigned char *p;
	const unsigned char *end, *end2;
	size_t len;
	mbedtls_x509_buf alg_id, alg_params;

	/* First set everything to defaults */
	*md_alg = MBEDTLS_MD_SHA1;
	*mgf_md = MBEDTLS_MD_SHA1;
	*salt_len = 20;

	/* Make sure params is a SEQUENCE and setup bounds */
	if (params->tag != (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
	}

	p = (unsigned char *)params->p;
	end = p + params->len;

	if (p == end) {
		return (0);
	}

	/*
	 * HashAlgorithm
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0)) == 0) {
		end2 = p + len;

		/* HashAlgorithm ::= AlgorithmIdentifier (without parameters) */
		if ((ret = mbedtls_x509_get_alg_null(&p, end2, &alg_id)) != 0) {
			return (ret);
		}

		if ((ret = mbedtls_oid_get_md_alg(&alg_id, md_alg)) != 0) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
		}

		if (p != end2) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
		}
	} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	if (p == end) {
		return (0);
	}

	/*
	 * MaskGenAlgorithm
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1)) == 0) {
		end2 = p + len;

		/* MaskGenAlgorithm ::= AlgorithmIdentifier (params = HashAlgorithm) */
		if ((ret = mbedtls_x509_get_alg(&p, end2, &alg_id, &alg_params)) != 0) {
			return (ret);
		}

		/* Only MFG1 is recognised for now */
		if (MBEDTLS_OID_CMP(MBEDTLS_OID_MGF1, &alg_id) != 0) {
			return (MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE + MBEDTLS_ERR_OID_NOT_FOUND);
		}

		/* Parse HashAlgorithm */
		if ((ret = x509_get_hash_alg(&alg_params, mgf_md)) != 0) {
			return (ret);
		}

		if (p != end2) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
		}
	} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	if (p == end) {
		return (0);
	}

	/*
	 * salt_len
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 2)) == 0) {
		end2 = p + len;

		if ((ret = mbedtls_asn1_get_int(&p, end2, salt_len)) != 0) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
		}

		if (p != end2) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
		}
	} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	if (p == end) {
		return (0);
	}

	/*
	 * trailer_field (if present, must be 1)
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 3)) == 0) {
		int trailer_field;

		end2 = p + len;

		if ((ret = mbedtls_asn1_get_int(&p, end2, &trailer_field)) != 0) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
		}

		if (p != end2) {
			return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
		}

		if (trailer_field != 1) {
			return (MBEDTLS_ERR_X509_INVALID_ALG);
		}
	} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + ret);
	}

	if (p != end) {
		return (MBEDTLS_ERR_X509_INVALID_ALG + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
	}

	return (0);
}
#endif							/* MBEDTLS_X509_RSASSA_PSS_SUPPORT */

/*
 *  AttributeTypeAndValue ::= SEQUENCE {
 *    type     AttributeType,
 *    value    AttributeValue }
 *
 *  AttributeType ::= OBJECT IDENTIFIER
 *
 *  AttributeValue ::= ANY DEFINED BY AttributeType
 */
static int x509_get_attr_type_value(unsigned char **p, const unsigned char *end, mbedtls_x509_name *cur)
{
	int ret;
	size_t len;
	mbedtls_x509_buf *oid;
	mbedtls_x509_buf *val;

	if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + ret);
	}

	if ((end - *p) < 1) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	oid = &cur->oid;
	oid->tag = **p;

	if ((ret = mbedtls_asn1_get_tag(p, end, &oid->len, MBEDTLS_ASN1_OID)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + ret);
	}

	oid->p = *p;
	*p += oid->len;

	if ((end - *p) < 1) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	if (**p != MBEDTLS_ASN1_BMP_STRING && **p != MBEDTLS_ASN1_UTF8_STRING && **p != MBEDTLS_ASN1_T61_STRING && **p != MBEDTLS_ASN1_PRINTABLE_STRING && **p != MBEDTLS_ASN1_IA5_STRING && **p != MBEDTLS_ASN1_UNIVERSAL_STRING && **p != MBEDTLS_ASN1_BIT_STRING) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
	}

	val = &cur->val;
	val->tag = *(*p)++;

	if ((ret = mbedtls_asn1_get_len(p, end, &val->len)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_NAME + ret);
	}

	val->p = *p;
	*p += val->len;

	cur->next = NULL;

	return (0);
}

/*
 *  Name ::= CHOICE { -- only one possibility for now --
 *       rdnSequence  RDNSequence }
 *
 *  RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
 *
 *  RelativeDistinguishedName ::=
 *    SET OF AttributeTypeAndValue
 *
 *  AttributeTypeAndValue ::= SEQUENCE {
 *    type     AttributeType,
 *    value    AttributeValue }
 *
 *  AttributeType ::= OBJECT IDENTIFIER
 *
 *  AttributeValue ::= ANY DEFINED BY AttributeType
 *
 * The data structure is optimized for the common case where each RDN has only
 * one element, which is represented as a list of AttributeTypeAndValue.
 * For the general case we still use a flat list, but we mark elements of the
 * same set so that they are "merged" together in the functions that consume
 * this list, eg mbedtls_x509_dn_gets().
 */
int mbedtls_x509_get_name(unsigned char **p, const unsigned char *end, mbedtls_x509_name *cur)
{
	int ret;
	size_t set_len;
	const unsigned char *end_set;

	/* don't use recursion, we'd risk stack overflow if not optimized */
	while (1) {
		/*
		 * parse SET
		 */
		if ((ret = mbedtls_asn1_get_tag(p, end, &set_len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET)) != 0) {
			return (MBEDTLS_ERR_X509_INVALID_NAME + ret);
		}

		end_set = *p + set_len;

		while (1) {
			if ((ret = x509_get_attr_type_value(p, end_set, cur)) != 0) {
				return (ret);
			}

			if (*p == end_set) {
				break;
			}

			/* Mark this item as being no the only one in a set */
			cur->next_merged = 1;

			cur->next = mbedtls_calloc(1, sizeof(mbedtls_x509_name));

			if (cur->next == NULL) {
				return (MBEDTLS_ERR_X509_ALLOC_FAILED);
			}

			cur = cur->next;
		}

		/*
		 * continue until end of SEQUENCE is reached
		 */
		if (*p == end) {
			return (0);
		}

		cur->next = mbedtls_calloc(1, sizeof(mbedtls_x509_name));

		if (cur->next == NULL) {
			return (MBEDTLS_ERR_X509_ALLOC_FAILED);
		}

		cur = cur->next;
	}
}

static int x509_parse_int(unsigned char **p, unsigned n, int *res)
{
	*res = 0;
	for (; n > 0; --n) {
		if ((**p < '0') || (**p > '9')) {
			return MBEDTLS_ERR_X509_INVALID_DATE;
		}
		*res *= 10;
		*res += (*(*p)++ - '0');
	}
	return 0;
}

static int x509_date_is_valid(const mbedtls_x509_time *time)
{
	int ret = MBEDTLS_ERR_X509_INVALID_DATE;

	CHECK_RANGE(0, 9999, time->year);
	CHECK_RANGE(0, 23, time->hour);
	CHECK_RANGE(0, 59, time->min);
	CHECK_RANGE(0, 59, time->sec);

	switch (time->mon) {
	case 1:
	case 3:
	case 5:
	case 7:
	case 8:
	case 10:
	case 12:
		CHECK_RANGE(1, 31, time->day);
		break;
	case 4:
	case 6:
	case 9:
	case 11:
		CHECK_RANGE(1, 30, time->day);
		break;
	case 2:
		CHECK_RANGE(1, 28 + (time->year % 4 == 0), time->day);
		break;
	default:
		return (ret);
	}

	return (0);
}

/*
 *  Time ::= CHOICE {
 *       utcTime        UTCTime,
 *       generalTime    GeneralizedTime }
 */
int mbedtls_x509_get_time(unsigned char **p, const unsigned char *end, mbedtls_x509_time *time)
{
	int ret;
	size_t len;
	unsigned char tag;

	if ((end - *p) < 1) {
		return (MBEDTLS_ERR_X509_INVALID_DATE + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	tag = **p;

	if (tag == MBEDTLS_ASN1_UTC_TIME) {
		(*p)++;
		ret = mbedtls_asn1_get_len(p, end, &len);

		if (ret != 0) {
			return (MBEDTLS_ERR_X509_INVALID_DATE + ret);
		}

		CHECK(x509_parse_int(p, 2, &time->year));
		CHECK(x509_parse_int(p, 2, &time->mon));
		CHECK(x509_parse_int(p, 2, &time->day));
		CHECK(x509_parse_int(p, 2, &time->hour));
		CHECK(x509_parse_int(p, 2, &time->min));
		if (len > 10) {
			CHECK(x509_parse_int(p, 2, &time->sec));
		}
		if (len > 12 && *(*p)++ != 'Z') {
			return (MBEDTLS_ERR_X509_INVALID_DATE);
		}

		time->year += 100 * (time->year < 50);
		time->year += 1900;

		CHECK(x509_date_is_valid(time));

		return (0);
	} else if (tag == MBEDTLS_ASN1_GENERALIZED_TIME) {
		(*p)++;
		ret = mbedtls_asn1_get_len(p, end, &len);

		if (ret != 0) {
			return (MBEDTLS_ERR_X509_INVALID_DATE + ret);
		}

		CHECK(x509_parse_int(p, 4, &time->year));
		CHECK(x509_parse_int(p, 2, &time->mon));
		CHECK(x509_parse_int(p, 2, &time->day));
		CHECK(x509_parse_int(p, 2, &time->hour));
		CHECK(x509_parse_int(p, 2, &time->min));
		if (len > 12) {
			CHECK(x509_parse_int(p, 2, &time->sec));
		}
		if (len > 14 && *(*p)++ != 'Z') {
			return (MBEDTLS_ERR_X509_INVALID_DATE);
		}

		CHECK(x509_date_is_valid(time));

		return (0);
	} else {
		return (MBEDTLS_ERR_X509_INVALID_DATE + MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
	}
}

int mbedtls_x509_get_sig(unsigned char **p, const unsigned char *end, mbedtls_x509_buf *sig)
{
	int ret;
	size_t len;
	int tag_type;

	if ((end - *p) < 1) {
		return (MBEDTLS_ERR_X509_INVALID_SIGNATURE + MBEDTLS_ERR_ASN1_OUT_OF_DATA);
	}

	tag_type = **p;

	if ((ret = mbedtls_asn1_get_bitstring_null(p, end, &len)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_SIGNATURE + ret);
	}

	sig->tag = tag_type;
	sig->len = len;
	sig->p = *p;

	*p += len;

	return (0);
}

/*
 * Get signature algorithm from alg OID and optional parameters
 */
int mbedtls_x509_get_sig_alg(const mbedtls_x509_buf *sig_oid, const mbedtls_x509_buf *sig_params, mbedtls_md_type_t *md_alg, mbedtls_pk_type_t *pk_alg, void **sig_opts)
{
	int ret;

	if (*sig_opts != NULL) {
		return (MBEDTLS_ERR_X509_BAD_INPUT_DATA);
	}

	if ((ret = mbedtls_oid_get_sig_alg(sig_oid, md_alg, pk_alg)) != 0) {
		return (MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + ret);
	}
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
	if (*pk_alg == MBEDTLS_PK_RSASSA_PSS) {
		mbedtls_pk_rsassa_pss_options *pss_opts;

		pss_opts = mbedtls_calloc(1, sizeof(mbedtls_pk_rsassa_pss_options));
		if (pss_opts == NULL) {
			return (MBEDTLS_ERR_X509_ALLOC_FAILED);
		}

		ret = mbedtls_x509_get_rsassa_pss_params(sig_params, md_alg, &pss_opts->mgf1_hash_id, &pss_opts->expected_salt_len);
		if (ret != 0) {
			mbedtls_free(pss_opts);
			return (ret);
		}

		*sig_opts = (void *)pss_opts;
	} else
#endif							/* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
	{
		/* Make sure parameters are absent or NULL */
		if ((sig_params->tag != MBEDTLS_ASN1_NULL && sig_params->tag != 0) || sig_params->len != 0) {
			return (MBEDTLS_ERR_X509_INVALID_ALG);
		}
	}

	return (0);
}

/*
 * X.509 Extensions (No parsing of extensions, pointer should
 * be either manually updated or extensions should be parsed!
 */
int mbedtls_x509_get_ext(unsigned char **p, const unsigned char *end, mbedtls_x509_buf *ext, int tag)
{
	int ret;
	size_t len;

	if (*p == end) {
		return (0);
	}

	ext->tag = **p;

	if ((ret = mbedtls_asn1_get_tag(p, end, &ext->len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | tag)) != 0) {
		return (ret);
	}

	ext->p = *p;
	end = *p + ext->len;

	/*
	 * Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
	 *
	 * Extension  ::=  SEQUENCE  {
	 *      extnID      OBJECT IDENTIFIER,
	 *      critical    BOOLEAN DEFAULT FALSE,
	 *      extnValue   OCTET STRING  }
	 */
	if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
		return (MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret);
	}

	if (end != *p + len) {
		return (MBEDTLS_ERR_X509_INVALID_EXTENSIONS + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
	}

	return (0);
}

/*
 * Store the name in printable form into buf; no more
 * than size characters will be written
 */
int mbedtls_x509_dn_gets(char *buf, size_t size, const mbedtls_x509_name *dn)
{
	int ret;
	size_t i, n;
	unsigned char c, merge = 0;
	const mbedtls_x509_name *name;
	const char *short_name = NULL;
	char s[MBEDTLS_X509_MAX_DN_NAME_SIZE], *p;

	memset(s, 0, sizeof(s));

	name = dn;
	p = buf;
	n = size;

	while (name != NULL) {
		if (!name->oid.p) {
			name = name->next;
			continue;
		}

		if (name != dn) {
			ret = mbedtls_snprintf(p, n, merge ? " + " : ", ");
			MBEDTLS_X509_SAFE_SNPRINTF;
		}

		ret = mbedtls_oid_get_attr_short_name(&name->oid, &short_name);

		if (ret == 0) {
			ret = mbedtls_snprintf(p, n, "%s=", short_name);
		} else {
			ret = mbedtls_snprintf(p, n, "\?\?=");
		}
		MBEDTLS_X509_SAFE_SNPRINTF;

		for (i = 0; i < name->val.len; i++) {
			if (i >= sizeof(s) - 1) {
				break;
			}

			c = name->val.p[i];
			if (c < 32 || c == 127 || (c > 128 && c < 160)) {
				s[i] = '?';
			} else {
				s[i] = c;
			}
		}
		s[i] = '\0';
		ret = mbedtls_snprintf(p, n, "%s", s);
		MBEDTLS_X509_SAFE_SNPRINTF;

		merge = name->next_merged;
		name = name->next;
	}

	return ((int)(size - n));
}

/*
 * Store the serial in printable form into buf; no more
 * than size characters will be written
 */
int mbedtls_x509_serial_gets(char *buf, size_t size, const mbedtls_x509_buf *serial)
{
	int ret;
	size_t i, n, nr;
	char *p;

	p = buf;
	n = size;

	nr = (serial->len <= 32)
		 ? serial->len : 28;

	for (i = 0; i < nr; i++) {
		if (i == 0 && nr > 1 && serial->p[i] == 0x0) {
			continue;
		}

		ret = mbedtls_snprintf(p, n, "%02X%s", serial->p[i], (i < nr - 1) ? ":" : "");
		MBEDTLS_X509_SAFE_SNPRINTF;
	}

	if (nr != serial->len) {
		ret = mbedtls_snprintf(p, n, "....");
		MBEDTLS_X509_SAFE_SNPRINTF;
	}

	return ((int)(size - n));
}

/*
 * Helper for writing signature algorithms
 */
int mbedtls_x509_sig_alg_gets(char *buf, size_t size, const mbedtls_x509_buf *sig_oid, mbedtls_pk_type_t pk_alg, mbedtls_md_type_t md_alg, const void *sig_opts)
{
	int ret;
	char *p = buf;
	size_t n = size;
	const char *desc = NULL;

	ret = mbedtls_oid_get_sig_alg_desc(sig_oid, &desc);
	if (ret != 0) {
		ret = mbedtls_snprintf(p, n, "???");
	} else {
		ret = mbedtls_snprintf(p, n, "%s", desc);
	}
	MBEDTLS_X509_SAFE_SNPRINTF;

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
	if (pk_alg == MBEDTLS_PK_RSASSA_PSS) {
		const mbedtls_pk_rsassa_pss_options *pss_opts;
		const mbedtls_md_info_t *md_info, *mgf_md_info;

		pss_opts = (const mbedtls_pk_rsassa_pss_options *)sig_opts;

		md_info = mbedtls_md_info_from_type(md_alg);
		mgf_md_info = mbedtls_md_info_from_type(pss_opts->mgf1_hash_id);

		ret = mbedtls_snprintf(p, n, " (%s, MGF1-%s, 0x%02X)", md_info ? mbedtls_md_get_name(md_info) : "???", mgf_md_info ? mbedtls_md_get_name(mgf_md_info) : "???", pss_opts->expected_salt_len);
		MBEDTLS_X509_SAFE_SNPRINTF;
	}
#else
	((void)pk_alg);
	((void)md_alg);
	((void)sig_opts);
#endif							/* MBEDTLS_X509_RSASSA_PSS_SUPPORT */

	return ((int)(size - n));
}

/*
 * Helper for writing "RSA key size", "EC key size", etc
 */
int mbedtls_x509_key_size_helper(char *buf, size_t buf_size, const char *name)
{
	char *p = buf;
	size_t n = buf_size;
	int ret;

	ret = mbedtls_snprintf(p, n, "%s key size", name);
	MBEDTLS_X509_SAFE_SNPRINTF;

	return (0);
}

#if defined(MBEDTLS_HAVE_TIME_DATE)
/*
 * Set the time structure to the current time.
 * Return 0 on success, non-zero on failure.
 */
#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
static int x509_get_current_time(mbedtls_x509_time *now)
{
	SYSTEMTIME st;

	GetSystemTime(&st);

	now->year = st.wYear;
	now->mon = st.wMonth;
	now->day = st.wDay;
	now->hour = st.wHour;
	now->min = st.wMinute;
	now->sec = st.wSecond;

	return (0);
}
#else
static int x509_get_current_time(mbedtls_x509_time *now)
{
	struct tm *lt;
	mbedtls_time_t tt;
	int ret = 0;

#if defined(MBEDTLS_THREADING_C)
	if (mbedtls_mutex_lock(&mbedtls_threading_gmtime_mutex) != 0) {
		return (MBEDTLS_ERR_THREADING_MUTEX_ERROR);
	}
#endif

	tt = mbedtls_time(NULL);
	lt = gmtime(&tt);

	if (lt == NULL) {
		ret = -1;
	} else {
		now->year = lt->tm_year + 1900;
		now->mon = lt->tm_mon + 1;
		now->day = lt->tm_mday;
		now->hour = lt->tm_hour;
		now->min = lt->tm_min;
		now->sec = lt->tm_sec;
	}

#if defined(MBEDTLS_THREADING_C)
	if (mbedtls_mutex_unlock(&mbedtls_threading_gmtime_mutex) != 0) {
		return (MBEDTLS_ERR_THREADING_MUTEX_ERROR);
	}
#endif

	return (ret);
}
#endif							/* _WIN32 && !EFIX64 && !EFI32 */

/*
 * Return 0 if before <= after, 1 otherwise
 */
static int x509_check_time(const mbedtls_x509_time *before, const mbedtls_x509_time *after)
{
	if (before->year > after->year) {
		return (1);
	}

	if (before->year == after->year && before->mon > after->mon) {
		return (1);
	}

	if (before->year == after->year && before->mon == after->mon && before->day > after->day) {
		return (1);
	}

	if (before->year == after->year && before->mon == after->mon && before->day == after->day && before->hour > after->hour) {
		return (1);
	}

	if (before->year == after->year && before->mon == after->mon && before->day == after->day && before->hour == after->hour && before->min > after->min) {
		return (1);
	}

	if (before->year == after->year && before->mon == after->mon && before->day == after->day && before->hour == after->hour && before->min == after->min && before->sec > after->sec) {
		return (1);
	}

	return (0);
}

int mbedtls_x509_time_is_past(const mbedtls_x509_time *to)
{
	mbedtls_x509_time now;

	if (x509_get_current_time(&now) != 0) {
		return (1);
	}

	return (x509_check_time(&now, to));
}

int mbedtls_x509_time_is_future(const mbedtls_x509_time *from)
{
	mbedtls_x509_time now;

	if (x509_get_current_time(&now) != 0) {
		return (1);
	}

	return (x509_check_time(from, &now));
}

#else							/* MBEDTLS_HAVE_TIME_DATE */

int mbedtls_x509_time_is_past(const mbedtls_x509_time *to)
{
	((void)to);
	return (0);
}

int mbedtls_x509_time_is_future(const mbedtls_x509_time *from)
{
	((void)from);
	return (0);
}
#endif							/* MBEDTLS_HAVE_TIME_DATE */

#if defined(MBEDTLS_SELF_TEST)

#include "tls/x509_crt.h"
#include "tls/certs.h"

/*
 * Checkup routine
 */
int mbedtls_x509_self_test(int verbose)
{
#if defined(MBEDTLS_CERTS_C) && defined(MBEDTLS_SHA1_C)
	int ret;
	uint32_t flags;
	mbedtls_x509_crt cacert;
	mbedtls_x509_crt clicert;

	if (verbose != 0) {
		mbedtls_printf("  X.509 certificate load: ");
	}

	mbedtls_x509_crt_init(&clicert);

	ret = mbedtls_x509_crt_parse(&clicert, (const unsigned char *)mbedtls_test_cli_crt, mbedtls_test_cli_crt_len);
	if (ret != 0) {
		if (verbose != 0) {
			mbedtls_printf("failed\n");
		}

		return (ret);
	}

	mbedtls_x509_crt_init(&cacert);

	ret = mbedtls_x509_crt_parse(&cacert, (const unsigned char *)mbedtls_test_ca_crt, mbedtls_test_ca_crt_len);
	if (ret != 0) {
		if (verbose != 0) {
			mbedtls_printf("failed\n");
		}

		return (ret);
	}

	if (verbose != 0) {
		mbedtls_printf("passed\n  X.509 signature verify: ");
	}

	ret = mbedtls_x509_crt_verify(&clicert, &cacert, NULL, NULL, &flags, NULL, NULL);
	if (ret != 0) {
		if (verbose != 0) {
			mbedtls_printf("failed\n");
		}

		return (ret);
	}

	if (verbose != 0) {
		mbedtls_printf("passed\n\n");
	}

	mbedtls_x509_crt_free(&cacert);
	mbedtls_x509_crt_free(&clicert);

	return (0);
#else
	((void)verbose);
	return (0);
#endif							/* MBEDTLS_CERTS_C && MBEDTLS_SHA1_C */
}

#endif							/* MBEDTLS_SELF_TEST */

#endif							/* MBEDTLS_X509_USE_C */
